135 resultados para MDC


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Dendritic cells (DCs) play critical roles in immune-mediated kidney diseases. Little is known, however, about DC subsets in human chronic kidney disease, with previous studies restricted to a limited set of pathologies and to using immunohistochemical methods. In this study, we developed novel protocols for extracting renal DC subsets from diseased human kidneys and identified, enumerated, and phenotyped them by multicolor flow cytometry. We detected significantly greater numbers of total DCs as well as CD141(hi) and CD1c(+) myeloid DC (mDCs) subsets in diseased biopsies with interstitial fibrosis than diseased biopsies without fibrosis or healthy kidney tissue. In contrast, plasmacytoid DC numbers were significantly higher in the fibrotic group compared with healthy tissue only. Numbers of all DC subsets correlated with loss of kidney function, recorded as estimated glomerular filtration rate. CD141(hi) DCs expressed C-type lectin domain family 9 member A (CLEC9A), whereas the majority of CD1c(+) DCs lacked the expression of CD1a and DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN), suggesting these mDC subsets may be circulating CD141(hi) and CD1c(+) blood DCs infiltrating kidney tissue. Our analysis revealed CLEC9A(+) and CD1c(+) cells were restricted to the tubulointerstitium. Notably, DC expression of the costimulatory and maturation molecule CD86 was significantly increased in both diseased cohorts compared with healthy tissue. Transforming growth factor-β levels in dissociated tissue supernatants were significantly elevated in diseased biopsies with fibrosis compared with nonfibrotic biopsies, with mDCs identified as a major source of this profibrotic cytokine. Collectively, our data indicate that activated mDC subsets, likely recruited into the tubulointerstitium, are positioned to play a role in the development of fibrosis and, thus, progression to chronic kidney disease.

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The forthcoming NIST’s Advanced Hash Standard (AHS) competition to select SHA-3 hash function requires that each candidate hash function submission must have at least one construction to support FIPS 198 HMAC application. As part of its evaluation, NIST is aiming to select either a candidate hash function which is more resistant to known side channel attacks (SCA) when plugged into HMAC, or that has an alternative MAC mode which is more resistant to known SCA than the other submitted alternatives. In response to this, we perform differential power analysis (DPA) on the possible smart card implementations of some of the recently proposed MAC alternatives to NMAC (a fully analyzed variant of HMAC) and HMAC algorithms and NMAC/HMAC versions of some recently proposed hash and compression function modes. We show that the recently proposed BNMAC and KMDP MAC schemes are even weaker than NMAC/HMAC against the DPA attacks, whereas multi-lane NMAC, EMD MAC and the keyed wide-pipe hash have similar security to NMAC against the DPA attacks. Our DPA attacks do not work on the NMAC setting of MDC-2, Grindahl and MAME compression functions.

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Multidisciplinary care (MDC) involves health professionals from a range of disciplines working together as a team (a multidisciplinary team – MDT) to deliver comprehensive care that addresses as many of a patient's needs as possible. Writing in 2011, Wilcoxon and others concluded: ‘Multidisciplinary care is accepted as best practice in cancer treatment planning and care.’ Yet their report (of the national audit of multidisciplinary cancer care in Australia) indicated that two-thirds of the surveyed hospitals did not have a MDT. Further, they found that where teams did exist, one-third of patients were not told that their case would be discussed by the team; the MDT-recommended treatment plan was not included in the patient’s record one-quarter of the time; and less than 1 per cent of teams reported routine attendance by the tumour-specific minimum core team. There is sparse case authority as to the potential medico-legal consequences of MDC by MDTs. This article raises five questions about legal aspects of MDC for consideration. The questions are not limited to cancer care, as MDTs are increasingly used in other areas of medicine.

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Despite international protection of white sharks Carcharodon carcharias, important conservation parameters such as abundance, population structure and genetic diversity are largely unknown. The tissue of 97 predominately juvenile white sharks sampled from spatially distant eastern and southwestern Australian coastlines was sequenced for the mitochondrial DNA (mtDNA) control region and genotyped with 6 nuclear-encoded microsatellite loci. MtDNA population structure was found between the eastern and southwestern coasts (F-ST = 0.142, p < 0.0001), implying female reproductive philopatry. This concurs with recent satellite and acoustic tracking findings which suggest the sustained presence of discrete east coast nursery areas. Furthermore, population subdivision was found between the same regions with biparentally inherited micro satellite markers (F-ST = 0.009, p < 0.05), suggesting that males may also exhibit some degree of reproductive philopatry; 5 sharks captured along the east coast had mtDNA haplotypes that resembled western Indian Ocean sharks more closely than Australian/New Zealand sharks, suggesting that transoceanic dispersal, or migration resulting in breeding, may occur sporadically. Our most robust estimate of contemporary genetic effective population size was low and close to thresholds at which adaptive potential may be lost. For a variety of reasons, these contemporary estimates were at least 1, possibly 2, orders of magnitude below our historical effective size estimates. Population decline could expose these genetically isolated populations to detrimental genetic effects. Regional Australian white shark conservation management units should be implemented until genetic population structure, size and diversity can be investigated in more detail.

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It is well known that Alamouti code and, in general, Space-Time Block Codes (STBCs) from complex orthogonal designs (CODs) are single-symbol decodable/symbolby-symbol decodable (SSD) and are obtainable from unitary matrix representations of Clifford algebras. However, SSD codes are obtainable from designs that are not CODs. Recently, two such classes of SSD codes have been studied: (i) Coordinate Interleaved Orthogonal Designs (CIODs) and (ii) Minimum-Decoding-Complexity (MDC) STBCs from Quasi-ODs (QODs). In this paper, we obtain SSD codes with unitary weight matrices (but not CON) from matrix representations of Clifford algebras. Moreover, we derive an upper bound on the rate of SSD codes with unitary weight matrices and show that our codes meet this bound. Also, we present conditions on the signal sets which ensure full-diversity and give expressions for the coding gain.

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Space-Time Block Codes (STBCs) from Complex Orthogonal Designs (CODs) are single-symbol decodable/symbol-by-symbol decodable (SSD); however, SSD codes are obtainable from designs that are not CODs. Recently, two such classes of SSD codes have been studied: (i) Coordinate Interleaved Orthogonal Designs (CIODs) and (ii) Minimum-Decoding-Complexity (MDC) STBCs from Quasi-ODs (QODs). The class of CIODs have non-unitary weight matrices when written as a Linear Dispersion Code (LDC) proposed by Hassibi and Hochwald, whereas the other class of SSD codes including CODs have unitary weight matrices. In this paper, we construct a large class of SSD codes with nonunitary weight matrices. Also, we show that the class of CIODs is a special class of our construction.

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A interleucina 13 (IL-13) tem sido apontada como um dos principais mediadores em processos de ativação de fibroblastos e indução de fibrose pulmonar, sendo, portanto, considerada como um alvo terapêutico importante. A silicose é uma doença pulmonar inflamatória crônica, de caráter ocupacional, caracterizada por uma intensa resposta fibrótica e granulomatosa. Com base nestas observações, tivemos por objetivo investigar o potencial efeito da administração da imunotoxina IL-13-PE38QQR (IL-13PE) sobre o modelo de silicose em camundongos. Camundongos Swiss-Webster foram anestesiados e instilados intranasalmente com partículas de sílica (10 mg), sendo a administração da IL-13PE (200ng/dia) realizada por via intranasal, uma vez ao dia em dias alternados no período entre 21 a 27 dias após a provocação. Analisamos o componente inflamatório, a deposição de colágeno e a área de granuloma avaliados através de técnicas clássicas de histologia, incluindo coloração com H&E e Picrus-sirius, ou ainda a quantificação do conteúdo de colágeno por Sircol. Os componentes de matriz extracelular fibronectina e laminina foram avaliados através de imunohistoquímica. Citocinas e quimiocinas foram quantificadas por sistema de ELISA. As medidas de função pulmonar e resposta de hiperreatividade foram realizadas através do sistema de pletismografia de corpo inteiro invasiva. Verificamos que o tratamento curativo com a IL-13PE inibiu de forma acentuada o comprometimento da função pulmonar nos camundongos silicóticos, incluindo tanto aumento da resistência como da elastância, assim como a resposta de hiperratividade das vias aéreas ao agente broncoconstrictor metacolina. De forma coerente, os animais silicóticos quando submetidos ao tratamento com IL-13PE apresentaram marcada redução do componente inflamatório pulmonar e da resposta fibrótica, atestado pela diminuição na produção de colágeno, laminina e fibronectina e redução importante da área de granuloma. De forma semelhante, as citocinas (TNF-α e TGF-) e quimiocinas (MIP-1α, MIP-2, TARC, IP-10, MDC) detectadas em quantidade aumentada no pulmão de animais silicóticos foram reduzidas pelo tratamento com a IL-13PE. Em conclusão, nossos resultados mostram que a administração curativa da IL-13PE foi capaz de inibir os componentes inflamatórios e fibróticos da fase crônica do quadro silicótico em camundongos, o que se refletiu de forma clara na melhora da função pulmonar. Em conjunto, nossos achados indicam que a utilização da IL13PE parece constituir uma abordagem terapêutica extremamente promissora para aplicação em casos de doenças crônicas de natureza fibrótica como a silicose.

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树突状细胞(dendritic cells, DC)作为机体天然免疫和获得性免疫反应的桥梁和枢纽,发挥着重要的启动和调控作用。随着体外诱导方法的建立和生物学技术的进步,有关DC 的基础生物学研究得到了快速的发展,在诱导方法、个体发生及基因表达和调控等方面,涌现出很多新的、未解的关键问题。同时,随着对粘膜免疫机理研究的深入,DC 在粘膜生态环境中的功能和影响,渐已成为免疫学研究前沿领域中的热点和要点。在本研究中,为了确定DC 体外分化成熟的最短时程,同时为了研究DC 分化成熟相关的基因表达调控,我们建立了快速的DC 体外诱导方法,分析了体外快速诱导 DC 的mi/mRNA 表达谱。此外,在原始分离的女性生殖道共生乳酸杆菌的基础上,以THP-1作为DC 前体细胞的细胞系模型,开展了女性生殖道共生乳酸杆菌刺激活化 THP-1 的研究,希望能够为乳酸杆菌作为生殖道粘膜免疫疫苗的应用提供理论基础。首先,采用外周血单个核细胞(peripheral blood mononuclear cells, PBMC)来源的CD14+细胞为DC 前体,经过GM-CSF 和IL-4 的刺激,1-6 天后得到未成熟DC (immature dendritic cells, iDC),并经成熟因子(TNF-α, IL-1β, IL-6 与PGE2)诱导 1-2 天后,获得成熟DC(mature dendritic cells, mDC)。经过比较和分析,明确了完全分化和成熟各2 天,即“2+2”,为DC 诱导分化的最佳和最短时程,从而证实和建立了DC 体外快速诱导的体系和方法。该方法获得的iDC 与mDC,具有与传统的“6+2” 方法获得的DC 相同的形态与表型,而且,利用该方法获得的DC 总数高于“1+1”, “1+2”与“6+2”的方法,为DC 的生物学研究提供了基础数据。我们进而采用芯片技术,对体外快速分化成熟的DC 进行了mi/mRNA 表达谱分析,确定了DC 不同分化发育阶段特征性的mi/mRNA 表达差异。结果发现,与CD14+ 单核细胞即DC 前体相比,iDC 与mDC 之间具有更加相近的mi/mRNA 表达方式。 miRNA 表达谱分析则表明,不同的miRNA 表达与DC 的不同分化和发育阶段相关。而且,位于同一基因簇内的miRNA,呈现协同表达的情况。特别值得注意的是,本研究发现了在DC 的某些发育阶段特异表达的miRNA,它们在DC 发育过程中的功能,还未得到诠释,它们在DC 某些分化阶段的特异表达,提示了DC 各分化阶段的相关性与特异性。结合mRNA 表达谱分析,我们发现miRNA 的表达与其目的基因的表达在mRNA 水平呈现负相关的特性。同时,免疫相关mRNA 与miRNA 在DC 体外不同发育阶段的表达亦呈现差异,其中,miRNA(如hsa-miR-181a, hsa-miR-223, hsa-miR-155, hsa-miR-146, hsa-miR-106a 与hsa-miR-20a 等)与mRNA(如ALM1 等)参与了特定的与免疫相关的GO(Gene Ontology)与通路(Pathway),提示这些miRNA 与mRNA 可能通过不同的方式调节控制着DC 的体外诱导过程。在有关粘膜生态环境中DC 的分化、成熟及其功能影响的研究中,我们首先通过各种乳酸杆菌鉴定方法的综合应用,确定了6 种原始分离的女性生殖道主要共生乳酸杆菌:发酵乳酸杆菌(L.Fermentum)、约氏乳酸杆菌(L.Johnsonni)、卷曲乳酸杆菌(L.Crispatus)、革氏乳酸杆菌(L.Gasseri)、詹氏乳酸杆菌(L.Jensenii)与德氏乳酸杆菌(L.Delbrueckii )。其中,德氏乳酸杆菌(L.Delbrueckii)和发酵乳酸杆菌(L.Fermentum)具有较高的产H2O2 的能力。在此基础上,我们在与THP-1 的共同培养体系中,将乳酸杆菌对DC 前体的作用和影响进行了比较和研究。结果发现,L.Crispatus 在分离的各原始菌株中,具有最强的刺激THP-1 活化的能力,而且,在相同刺激比例下,L.Crispatus 活菌具有比死菌更强的免疫刺激能力,表现为明显上调THP-1 细胞表面标志CD40、CD80、CD86、 CD1a、CCR6 与CD324 的表达水平,同时可诱导活化THP-1 上调表达Th1 型细胞因子。通过FITC-Dextran 吞噬实验,我们发现,经过L.Crispatus 刺激的THP-1 细胞,其吞噬外来抗原的能力明显下降,但尚未检测到经过活化的THP-1 细胞刺激T 细胞增殖的能力。通过流式细胞术分析的方法,我们检测了TLR1、TLR2、TLR4 与TLR6 在不同的刺激分化阶段的表达水平,结果表明,THP-1 主要通过TLR2 与TLR6 识别女性生殖道L.Crispatus。综上所述,本研究首先通过对DC 体外分化成熟的最短时程的分析,确立了快速诱导DC 的最佳方法,进而利用芯片技术,研究了快速诱导DC 的mi/mRNA 表达谱,揭示了DC 体外分化发育过程中可能的调控途径,为进一步研究DC 的基础生物学提供了恰当的模型和具有指向性的线索。同时,通过与DC 前体THP-1 的共同培养体系,证实了生殖道共生乳酸杆菌的免疫调节作用,为以乳酸杆菌为载体的生殖道粘膜免疫疫苗的研究和应用提供了实验依据

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本论文主要由3 个相对独立的部分组成:中国恒河猴单核细胞来源的树突 状细胞的表型及功能研究;外周血DC 亚群在SIVmac239 感染的中国恒河猴中 数量及细胞因子的变化以及急性感染期SIVmac239 对中国恒河猴外周血DC 亚 群的凋亡和免疫表型的影响。 非人灵长类动物是人类的近亲,由于在组织结构、免疫、生理和代谢等诸 多方面与人类高度近似,科学界较普遍地利用非人灵长类作为动物模型来进行 艾滋病(AIDS)的发病机制和疫苗研究。中国恒河猴发病缓慢,更适合于HIV 感染的相关研究。在本研究中,我们在体外成功培养了中国恒河猴单核细胞来 源的树突状细胞(monocyte derived dendritic cells,MDDC),并测定其表型和免 疫刺激功能。通过GM-CSF 和IL-4 共同刺激培养单核细胞6 天以后便获得了未 成熟MDDC,随后加入IL-1β、PGE2、LPS 和TNF-α 联合刺激MDDC 成熟。 成熟的MDDC 上调了共刺激分子和CD83 的表达,具有很强的刺激T 淋巴细胞 增殖的能力并分泌大量的IL-12。本研究为后续的DC 疫苗研究奠定了基础。 我们实验室建立了SIVmac239 感染的中国恒河猴动物模型。以该模型为依 托,我们研究了外周血中DC 亚群在急性感染期以及慢性感染期的数量、表型 及功能变化。DC 作为最重要的连接先天免疫与获得性免疫的抗原递呈细胞, 在AIDS 发病进程中扮演着重要的角色。研究发现AIDS 患者血液和淋巴结中 髓样DC(myeloid DC,mDC)和浆细胞样DC(plasmacytoid DC,pDC)会随 着感染的进程而减少,并且伴随着功能损伤。本论文通过研究发现,中国恒河 猴的DC 亚群数量在感染后尽管波动十分剧烈,但并没有显著性地增加或减少, 中文摘要 2 在后期DC 数量能够回升到正常的范围之类,这种回升不同于印度恒河猴,很 可能是中国恒河猴缓慢发病的原因之一。进一步通过研究体外刺激DC 亚群分 泌的细胞因子,我们发现在急性感染期,pDC 分泌的IFN-α 显著提高,并很可 能刺激mDC 成熟并促进了IL-12 的分泌。早期大量细胞因子的分泌有助于控制 病毒复制,但同时也激起了整个免疫系统的活化,促进了疾病进程。而在整个 感染阶段,IFN-α 与CD4+ T 细胞呈正相关,而与病毒载量呈负相关,表明了 IFN-α 对于延缓疾病进程具有重要的意义。 我们测定了急性感染期DC 亚群受病毒影响而发生的表型变化,发现pDC 更容易受到病毒影响而发生凋亡,这可能与pDC 高表达SIV 受体CD4 和CCR5 有关。在感染过程中,尽管mDC 和pDC 都显著地下调了CD4 表达,而上调了 CCR5 的表达,不过仅发现pDC CD4 的表达与病毒载量呈负相关,而CCR5 的 表达与病毒载量呈正相关。在此过程中DC 亚群都会因为病毒的影响而活化, 继而提高CCR7 的表达。同时无论mDC 还是pDC,其表达的CD80 和CD86 都与病毒载量呈正相关。在早期感染中,DC 的活化促使整个免疫系统针对病 毒发挥免疫反应,对于控制疾病发展具有重要意义。

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Video compression techniques enable adaptive media streaming over heterogeneous links to end-devices. Scalable Video Coding (SVC) and Multiple Description Coding (MDC) represent well-known techniques for video compression with distinct characteristics in terms of bandwidth efficiency and resiliency to packet loss. In this paper, we present Scalable Description Coding (SDC), a technique to compromise the tradeoff between bandwidth efficiency and error resiliency without sacrificing user-perceived quality. Additionally, we propose a scheme that combines network coding and SDC to further improve the error resiliency. SDC yields upwards of 25% bandwidth savings over MDC. Additionally, our scheme features higher quality for longer durations even at high packet loss rates.

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Recent years have witnessed a rapid growth in the demand for streaming video over the Internet and mobile networks, exposes challenges in coping with heterogeneous devices and varying network throughput. Adaptive schemes, such as scalable video coding, are an attractive solution but fare badly in the presence of packet losses. Techniques that use description-based streaming models, such as multiple description coding (MDC), are more suitable for lossy networks, and can mitigate the effects of packet loss by increasing the error resilience of the encoded stream, but with an increased transmission byte cost. In this paper, we present our adaptive scalable streaming technique adaptive layer distribution (ALD). ALD is a novel scalable media delivery technique that optimises the tradeoff between streaming bandwidth and error resiliency. ALD is based on the principle of layer distribution, in which the critical stream data are spread amongst all packets, thus lessening the impact on quality due to network losses. Additionally, ALD provides a parameterised mechanism for dynamic adaptation of the resiliency of the scalable video. The Subjective testing results illustrate that our techniques and models were able to provide levels of consistent high-quality viewing, with lower transmission cost, relative to MDC, irrespective of clip type. This highlights the benefits of selective packetisation in addition to intuitive encoding and transmission.

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Bandwidth constriction and datagram loss are prominent issues that affect the perceived quality of streaming video over lossy networks, such as wireless. The use of layered video coding seems attractive as a means to alleviate these issues, but its adoption has been held back in large part by the inherent priority assigned to the critical lower layers and the consequences for quality that result from their loss. The proposed use of forward error correction (FEC) as a solution only further burdens the bandwidth availability and can negate the perceived benefits of increased stream quality. In this paper, we propose Adaptive Layer Distribution (ALD) as a novel scalable media delivery technique that optimises the tradeoff between the streaming bandwidth and error resiliency. ALD is based on the principle of layer distribution, in which the critical stream data is spread amongst all datagrams thus lessening the impact on quality due to network losses. Additionally, ALD provides a parameterised mechanism for dynamic adaptation of the scalable video, while providing increased resilience to the highest quality layers. Our experimental results show that ALD improves the perceived quality and also reduces the bandwidth demand by up to 36% in comparison to the well-known Multiple Description Coding (MDC) technique.

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Genetic or vitamin D3-induced overexpression of thymic stromal lymphopoietin (TSLP) by keratinocytes results in an atopic dermatitis (AD)-like inflammatory phenotype in mice echoing the discovery of high TSLP expression in epidermis from AD patients. Although skin dendritic cells (DC) are suspected to be involved in AD, direct evidence of a pathogenetic role for skin DC in TSLP-induced skin inflammation has not yet been demonstrated. In a mouse model of AD, i.e. mice treated with the low-calcemic vitamin D3 analogue, MC903, we show that epidermal Langerhans cells (LC)-depleted mice treated with MC903 do neither develop AD-like inflammation nor increased serum IgE as compared to vitamin D3 analogue-treated control mice. Accordingly, we show that, in mice treated with MC903 or in K14-TSLP transgenic mice, expression of maturation markers by LC is increased whereas maturation of dermal DC is not altered. Moreover, only LC are responsible for the polarization of naive CD4+ T cells to a Th2 phenotype, i.e. decrease in interferon-gamma and increase in interleukin (IL)-13 production by CD4+ T cells. This effect of LC on T-lymphocytes does not require OX40-L/CD134 and is mediated by a concomitant down-regulation of IL-12 and CD70. Although it was previously stated that TSLP up-regulates the production of thymus and activation-regulated chemokine (TARC)/chemokine (C-C motif) ligand 17 (CCL17) and macrophage-derived chemokine (MDC)/CCL22 by human LC in vitro, our work shows that production of these Th2- cell attracting chemokines is increased only in keratinocytes in response to TSLP overexpression. These results demonstrate that LC are required for the development of AD in mouse models of AD involving epidermal TSLP overexpression.

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The practical knowledge has characteristics of a process with peculiar idiosyncrasies that require disruption with preconceived ideas, dialogue, negotiation and joint action. The knowledge underlying remains unclear despite of being what informs decision making. It is academia’s responsibility to unveil and nominate knowledge and that is the reason why we conducted two studies with clinical nurses. The aim is to understand the social representation that nurses make of their knowledge about nursing and analyze their clinical practices. In one of the studies, based on the theoretical-methodological referential of social representations, we used the technique of free association of words with the stimulus “knowledge in nursing”. In another study, developed within a naturalistic context and under the “Grounded Theory” referential, we used non-participative observation and explanatory interviews. From the first study we identified the structure of social representations of knowledge in nursing, from which emerged the central core constituted by four elements (Investigation, Wisdom, help Relation, Competence) and a second periphery with one element (Reflection). With the second study we identified that decisions are made within a dynamic, systematic and continuous process of diagnostic evaluation and clinical intervention using the various types of knowledge (e.g. clinic, experiential, scientific, personal). We concluded that the various types of knowledge in nursing, represented by the expressions mentioned above, are systematically and creatively mobilized within the dynamic process of diagnostic evaluation and clinical intervention. It is therefore important to unveil and nominate the different knowledge implicit in the clinical practice and Academia should be responsible for that task.